1. Field of the Invention
This invention relates to data recording apparatus, and more particularly, to a multi-channel data recorder apparatus for recording event data and encoded time and date information to provide a time reference for the event data.
2. Description of the Prior Art
Many types of data recording apparatus are employed to record event data for various purposes. Examples of such data recording apparatus include load survey recorders, billing recorders, or the like which are employed by the utility industry to obtain data for use in customer study analysis, load surveys, load monitoring, automatic billing, data collecting and the like. In such recorders, it is generally desirable to provide a time reference for the recorded data.
One such survey recorder disclosed in the U.S. Pat. No. 3,829,772 to Normal F. Marsh et al., entitled "Load Survey Recorder for Measuring Electrical Parameters", comprises a two-track cassette recorder including recorder circuitry having a data recorder section which is responsive to input pulses representing a measurement for recording data pulses on a first track of a magnetic tape, and a time recorder section which is responsive to timing pulses to record time data on the second track of the tape to identify predetermined time intervals in which data recording occurs. The data relating to a load measured by the utility meter along with the time reference is recorded on the tape in a form which is compatible for use with available data processing equipment.
At a time determined by the nature of the usage of the equipment, the cassette tape is removed from the survey recorder and returned to a processing center where the tape is played back over tape processing equipment to retrieve the recorded information which may be supplied to a computer for processing.
In the patented survey recorder, timing pulses are recorded on the tape at predetermined intervals, such as at one pulse every fifteen minutes. Accordingly, when the load survey data is processed, the reference timing pulses must be converted to "real time" to determine the demand intervals at selected hours of a given day. Since the tape cassettes employed in such survey recorders typically record data for a period of approximately one month, it is evident that the conversion of the time reference to a given day, or to a given hour of the day is difficult and time consuming.
Also, while the patented system provides data which is compatible for use with available data processing equipment and permits printout of the recorded data in a conventional computer print out, in some instances, it may be desirable to provide a visual display of the data as the data is being processed.
A further consideration is identification of the data source. Normally, an identifying code such as the serial number of the utility device being monitored is hand written on the cassette cartridge to identify the utility device which provided the data when the recorded cassette is returned to a processing center. In the event the tape cassette is not marked to identify the utility meter, it may be impossible to determine the source of the data being processed.
Therefore, it would be desirable to have a data recording apparatus which provides a more precise time reference for recorded event data. It would also be desirable to have a data recording apparatus which records data in a format which is suitable for driving a conventional display apparatus, such as a segmented light emitting diode display unit. It would also be desirable to have a data recording apparatus which automatically records an identification number for the source of the recorded event data.